A crafty 9-year-old boy who recently captured headlines after he skipped security at the Minneapolis-St. Paul International Airport then boarded a Delta flight to Las Vegas has been revealed to be a "challenging" kid with a rap sheet. And according to his father, "I don't have an angel."

A Hennepin County official noted in the Star Tribune that prior to the boy's stowaway stunt, he had stolen a car and sneaked into a water park without paying. He was also on the radar of child protection investigators.

In an email obtained by the Star Tribune, Janine Moore, area director for Hennepin County's Human Services and Public Health Department, noted that since December 2012, four child-protection assessments have been conducted on the boy's family.

"The reports have been inconsistent and there have been no injuries to the child; however, there is a pattern of behavior," Moore wrote in the email.

In an interview with CNN, the boy's father admits that "I don't have an angel" but maintains that he and the boy's mother, who works at the airport, are not bad parents.

The boy's mother reported him missing last Thursday morning, one day after he left the couple's home to take out the trash.

"We're not bad parents. We didn't think nothin' of it," the father told CNN. "We thought he was at his friend's house."

"I don't understand," he continued. "You've got so (many) security checks at these airports. How can you let a 9-year-old sneak past security, get on the plane, without anyone stopping him, questioning him or anything?"

In a KARE 11 report on Monday, airport spokesperson Pat Hogan called the boy's stunt a "rare incident" and said the matter was being handled by Delta and TSA.

Delta officials noted in a statement to KARE 11 that: "We are investigating the incident and cooperating with the agencies involved." The sentiment was echoed by the TSA.

In the meantime, many observers have been scratching their head over what happened.

"It's crazy," Ryan Linderman noted to KARE 11, while passing through MSP airport Saturday. "I have an 8-year-old and that freaks me out."

"He had to pass three levels of security," said Terry Trippler, an air travel expert with ThePlaneRules.com. "You have the TSA, the gate agents, and the flight crew and a child comes through without even a seat assignment."